Indeed, practice builds confidence and will enable you to launch easily by yourself. A number of club members launch trailered boats on their own, including me.
Wick, Mudeford and Lymington are particually good places to lauch single handed. And Baiter is possible with the use of a rope if you don't fancy dunking the car.
Often you will find depening on the crew you take it can be like launching on your own!!
Going out with others just to see how they launch and recover will give you a great insight on how to (and some times not to) do it.
Even better, take a picnic and go to a slipway on a sunny weekend guranteed entertainment and an oppourtunity to learn!
Rob